This invention relates to an improved printing head capable of being mounted on a portable label printing machine, or the like. More particularly, the invention relates to a printing head which is provided with a plurality of printing devices. The printing head is used for simultaneously printing multi-line indicia such as price, size, production date and/or administrative numbers on labels or price tags which are applied or attached to desired articles such as commodities.
The printing head herein is of the belt type which carries endless stamp belts having on their outer surfaces several type elements for printing indicia, such as numerals, marks and symbols. This type of printing head for printing plural line indicia on labels includes printing devices for printing prices, dates, etc. Each such printing device generally comprises a plurality of large-diameter rotation wheels, each for selectively driving a respective stamp belt, and a plurality of small-diameter rotation pieces, each for supporting the respective stamp belt in the print region. Such printing devices are integrally mounted on a housing to form a plural line printing head.
In this type of printing head, the widths of the upper end large diameter rotation wheels, when printing devices are arrayed next to each other in a printing head define the minimum distance that can be placed between the type elements of stamp belts on both of the printing devices in the printing heads. Thus, the distance between two lines of type elements cannot be reduced. In practice, therefore, only indicia with large spacing between adjacent print lines are printed.
In certain situations, it is also desirable to set precisely controlled spacing between adjacent lines of print. But, known printing heads have preset interline spacing and do not permit interline spacing variation.
Also, it is desirable to control precisely where indicia will be printed along a label. But, known printing heads only permit printing at preset and quite difficult to vary locations on the label.